Electric metal-working apparatus.



A. F. RIETZBL in G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APPLIGATION FILED NOV. 20, 1908.

Patented Mar. 30, 1915.

l2 SHEETS-SHEET l.

z twas cusv A. F. RIBTZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APILIGATION FILED NOV. 20. 1908.

Patented Mar. 30, 1915.

12 SHEETS-SHEET 2.4

A. RIETZEL. n G. E. BARSTOW.

ELEGTRIGMETAL WORKING APPARATUS.

APPLIGATION FILED NO\`.20, 1908.

Patented Mal. 30, 1915.

12 SHEETSSHEET 3.

E E E @illnesses Mfg A. F. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS. APPLICATION FILED NOV. 20, 1908.

Patented Mar. 30, 1915.

A. F. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

Patented Mar. 30, 1915.

X2 SHBBTSASHEBT 5.

APPLICATION FILED NOV. 20. 1908.

A. I'. RIIITZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APPLICATION FILED NOV. Z0, 1908.

ma M j wm NH .3 L Wj rml.

6 M d2 of 0 m.. 4 a f3. nw 3 MV/ a Z P. 7J M ,f 0 0/ L. 3 a 4 W x A. F. RIETZEL & G. B. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APPLICATION FILED NOV. 20. 1908. 1,133,578. Patented Mar.30,1915.

12 SHEETS-SHEET 7.

Q N m n( N) C0 0o lq Q CQ a lo Q Q5@ l\ an .O l.

Q o o o; o A Q Q Q jr: ver: fo 715 v A jm" e aff row @27 ff M@ A. E. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APPLICATION FILED NOV. 20. 1908. 1,133,578. Patented Mar. 30, 1915.

12 SHEETS-SHEET 8.

A. E. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

APPLICATION FILED NOV. 20, 1908. Patented Mar. 30, 1915.

12 SHEETS-SHEET 9.

A. F. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS. APPLICATION HLED Nov. 2o, 1908.

Patented Mar. 30, 1915.

12 SHEETS-SHEET 10.

A. P. RIETZEL & G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS. APPLICATION FILED Nov. 2o. 1908. 1,1 33,578. Patented Mar. 3o, 1915.

12 SHEETS-SHEET 11.

A. F. RIETZEL a G. E. BARSTOW.

ELECTRIC METAL WORKING APPARATUS.

` APPLICATION FILED Nov. zo, 190s. 1, 1 33,57 8.

Patented Mar. 30, 1915.

l2 SHEETSSHBET 12. /af/ /08 If? 0 9 UNITED STATES PATENT oEEICE.`v`

ADOLPH P. RIETzEL, OE CHARLESTOWN, RHODE IsLAND, AND GEORGE E. RARsTow, or

LYNN, MASSACHUSETTS, ASSIGNORS, vRv MESNE ASSIGNMENTS, To THOMSON ELEC- TRIC WELDING COMPANY, A CORPORATION OE MASSACHUSETTS.

ELECTRIC METAL-WORKING APPARATUS.

To all 'whom it may concern: i

Be it known that we, ADOLPH F. RIETZEL and GEORGE E.' BARsTow, citizens of the United States, and residents of Charlestown, in the county Of Washington and State of Rhode Island, and Lynn, in the county of lsieX and State of Massachusetts, respectively, have-invented certain newl and useful Improvements in Electric Metal-Working Apparatus, of which the following is a speciiication.

Our invention relates to an electric metal working apparatus wherein .the work is heated to the desired extent by the passage same time that the heating current is caused to pass through the section to be welded or otherwise worked.

A further object is to provide a machine which will' automatically feed the work to the heating contacts to form a. continuous welded joint, and" automatically control the passage of the heating currentthrough the section of metal to be welded.

A special object of our invention is to provide a machine in which the seams of cans, pots or other sheet vmetal goods can be welded together by passing electric currents through the same at the same time that the Work is progressively fed throughthe maxchine whereby the finished article will be smoother in appearance and cheaper to obtain than heretofore.

Our invention will/herein be shownand described as applied to a'machine for Welding the seams of sheet metal cans or the like,

but it will-be understood that it is not lmited to this application of it, as varlous other uses of the invention might be employed without departing from the spirit' thereof.

To these ends our invention consists in providing'an electric metal working apparatus with means whereby thek section of work to be welded is progressively fed into p engagement with the contacts together with means for maintaining the flow of electric from the work at a pre .holding means and permit the circuit to be y Specification of Letters Patent. Patented Mar, 30, 1915. Application led November 20, 1908. Suerial N o. 463,536.

' fed to electric contacts with means whereby one vof the 'contacts is automatically freed 65 from the work after it has progressed and the weld eifectedfor a predetermined distance. p

The inventionconsists further in providing means whereby one of the contacts is 'm held out of engagement with the work and means for releasing the contact from the holding means automatically controlled by the movement of the work to permit the contact to engage the work.

The invention consists still further in providing means for disenigaging one Contact etermined point in.

the movement of the work and in causing it to engage the work at another Oint, said 8o engaging and disengaging of t e Contact with the work being automatically controlled by the movement of the work itself.

The invention consists still further in providingv a single adjustment forl controlling -the time of automatic stopping of the feedcuit providing the heating current. It also consists in v means for holding the circuit open and a work-holder adapted to free said closed at a predetermined point in the move- `ment of the' work-holder.

` The invention Still further consists in providing an electric metal working apparatus with a travelingucontact and a stationary contact, the-traveling contact being adapted to 'feed the work into progressive engagement with the stat'onary contact. l

The invention further consists in providing means for sup orting the entire length of the work toe we ed or Otherwise Ico y worked, said support being adapted to travel to feed the work progressively to the other contact and in electrical connection with one or at the end of the terminal of the source of current supplyy during said travel. A.

The invention consists still further Ain means for` clamping the work along the whole length of in means for adjusting the edge, particularl'y for the amount of lap desired, in cases where a lap Weld is to be made.

Our invention consists still further in the details of construction and combinations of parts hereinafter more particularly described and then specified in the claims.

In the accompanying drawings, Figure 1 illustrates a front elevation of an electric metalworking apparatus constructed in accordance with our invention. Fig. 2 ,is a side elevation of the same. Fig. 3 is an enlarged view of the traveling carriage, contact-raising devices and circuit controlling devices detached from the rest of the apparatus and shown in their position before beginning the forward movement of the carriage, parts being broken away. Fig. 4 is a Similar view showing the various devices in their positions when the carriage has traveled part of its predetermined distance. Fig. 5 is a similar view showing the position of the devices after completing the weld forward travel of the carriage. Fig. 6 is a front elevation of the gear train and clutch for returning the carriage to its original position after completing the weld. Fig. 7 is a side elevation, on alrenlarged scale, of the clutch and operating parts shown in Fig. 6. Fig. 8 is a front elevation and partial section of the device for maintaining electrical connection between the traveling carriage and one termnal of the transformer secondary, the section being taken on the line P P Fig. 19. Fig. 9 is a transverse section on the line S S Fig. 8. Fig. 10 is a front elevation of the slide for the upper contact and its supporting arts. Fig. 11 is an enlarged transverse vertical section through the upper or stationary contact and supporting parts. Fig. 12 is an enlarged horizontal transverse section through the upper or stationary contact taken on the line Y Y Fig. 1. Fig. 13 is a view of the circuit controller in open osition, the controlling devices therefor being shown in the position when the carriage is about tocommence its forward movement. Fi 14 is an enlarged side view of the contro ling devices for the circuit breaker. Fig. 15 is a similar view to Fig. 13, showing the circuit closer in closed position and the controlling devices in the position taken during the forward movement of the carriage. Fig. 16 is a similar view showing the circuit closer in open position; the controlling 55 devices being shown in position taken when the weld and also in providthe carriage has reached the end of its forward movement. F ig.`17 is a front elevation o f the entire gear train detached from theapparatus. Fig. 18. is a frontelevation, parts being broken away, of the stationary contact, the brush connection therefor and the cleaner for the edge of the contact. Fig. 19 is an enlarged plan view of the carriage and work supporting and clamping parts one .set of locating fingers being removed and the guards for the roller contacts being also omitted for clearness. Fig. 20 is a transverse vertical section on the line M M Fig. 19. Fig. 21 is an enlarged transverse vertical section on the 'line O O Fig. 19. Fig. 22 is a side elevation of the shaft forthe locating devices. Fig. 23 is an end view of the same. Fig.` 24 is .an enlarged view of the means ,for adjusting the amount of lap for the weld. Fig. 25 is an enlarged detached view of the devices for controlling' the travel of the carriage. Fig. 26 is an end view looking in the direction of the arrow A Fig. 25. Fig. 27 is an enlarged front elevation of the driving mechanism for the carriage. Fig. 28 is an enlarged transverse section through the carriage on the line X X Fig. 3, and showing the clutch and driving mechanism for propelling the Vcarriage in side elevation. Fig. 29 is a transverse section taken on the llne Z Z Fig. 25. Fig. 30v

.is a detached view of the mechanism for automatically disconnecting the carriage from the driving power, the mechanism being shown in the position taken after the carriage has been uncoupled. y

.Inthe preferred form of carrying out our invention in a machine in which it is desired to effect a lap weld in sheet metal goods as illustrated in the accompanying drawings, 1 supported upon a suitable framework, the front frame being indicated at 2 and the rear one at 3, the said frames being secured to and rising from a suitable base 4.

The source of electric energy adapted to supply heating current to the work might be of any desired type, but is here shown as a transformer provided with a iiexible secondary such as is well-known in the art. The transformer is suitably vsecured to, but insulatedv from a frame 5 rising from the base 4 at the rear of the apparatus and consists of a primary 6 and a flexible secondary 7 constructed preferably of a lnumber of thin copper strips, to the ends of which are secured the contacts which engage the work as will be hereinafter described. The laminated core for the transformer is indicated at 8.

A laten 9, hereinafter called a carriage, working in suitable guides 10, 10 secured to the 'table 1, travels forward and back over an opening 11 (see Fig. 28) in the table 1. Referring more particularly to Figs. 3,

indicates a table or platform sulated from a post or standard 13 rising from the carriage9 carries an overhanging slide 14 preferably secured to the bracket 12 bv means of vertical guides 15,15 in which it is free to move vertically. The.

slide 14 travelsvforward and back with the carriage 9 on ways 17 supported by, but insulated from a bracket 16 mounted on the rear of the table 1. The ways 17 are secured to one terminal of the flexible secondaryT of the transformer and are provided on the upper surfacet with a rack of` copper rollers 18 upon which the overhanging portion of the slide 14 travels and through which it conducts heating current from one terminal of the secondary to the bracket 12. To allow for irregularities in the size of the copper rollers 18 and to insure that the slide will always be in contact with them throughout its travel, the slide 14 is preferably secured to the `bracket 12 by. the vertical guides 15, 15 in whichvit can move vertically to follow whatever unevenness there may be in the rollers 18, the slide being continually pressed on the rollers by a spring 19 seated on a shoulder projecting from the slide 14 and compressed between it and the fixed bracket 12, a suitable adjusting screw 20'being provided to regulate the amount of pressure exerted on the rollers 18. Covers or guards 21, 22 preferably constructed of sheet metal, are secured to either end of the overhanging portion of the slidex14 and project longitudinally therefrom so that the roller contacts y18 will be protected from dust, dirt, etc.,

at all times irrespective of the position of the slide 14.

The work-holder or support for the work ismounted on and travels with the carriage 9 and when it is desired to weldthe seam of'a hollow article such as a can, the workholder or 'support preferably takes the form of a horn or mandrel 23`constructed of some 'conducting material such as copper and preferably circular in cross-section.

The horn or mandrel is provided with a squared end which seats in a recess formed inthe bracket 12 to which it is firmly secured and in electrical connection therewith. The hornor mandrel 23, hereinafter called the work-holder or work support projects from the bracket 12 for a sufficient distance to provide support for the whole length of the seam to be Welded. Preferably the workholder is provided with a` removable contact-shoe 24 secured in a groove therein and upon said shoe the seam is placed, so that, should the line of contact become worn or damaged, a new shoe could readily be inserted without being put to the expense of providing an entire new mandrel. The free end of the work-holder is supported by a removable post 25 pivotally mounted on a slide.

25 is returned to its supporting position, the

free end thereof snaps under a catch 28 secured to the end of the horn, the catch being held extended by a spring 29 to prevent the post freeing itself from the mandrel.

By the construction fdescribed above, it

.will be seen that electrical connection is maintained between the Work-holder or support 23 and one terminal of the exible secondary 7 ofthe transformer.

Referring more particularly to Figs. 1, 2, 10, 11 and 12, 30 indicates a bracket mounted on the frames 5 and to the face of which is secured vertical guide-Ways 31, 32, the said bracket being suitably insulated from the guide-Ways as shown. An `inverted U- Vshaped slide 33 Working in the guide-Ways 31, 32 moves transversely with respect to the line of travel of the Work-support 23 and has secured to it a block of conducting material 34. The block 34 is secured to the slide 33 so that it travels With it, but it is also capable of being adjusted vertically onthe This vertical movement or adjustment is accomplished by providing the sides of the blcck 34 with vertical grooves in which the inner sides of the U-shaped slide 33 Work and suspending the block Within the slide. The block is rigidly secured to the slide 33 so that it practically becomes part thereof by a headed screw 35 secured to the slide 33 by -suitable nuts 36, the head of the screw being seated in a recess in the top of the block 34 and secured thereto by a plate 37 fastened to the block 34 land provided vwith an opening through which the screw 35 passes. Adjustment of the position of the block 34 is attained by loosening the lower nut 36 and turning the upper nut in either direction to raise or lower the block as desired, after which the llower nut is jammed up andthe yblock 34 becomes a rigid part of the slide 33./ The block 34 is secured to the other terminal of the flexible secondary 7 of thc transformer and in electrical connectionV therewith so that current will flow from the secondary to the conducting block 34. Preferably the upper contact for the work which is carried by block 34, is of circular form and free to revolve so as to present a new surface to the work as it is progressively. fed into engagement with it by the travel of the carriage 9. The rotary movement of the upper crntact is attained as follows:

A spindle 38 of conducting material is journaled in the block 34 and free to rotate the conducting l therein but is secured against longitudinal movement by a shoulder 38 engaging the front face of the block 34 and a collar 39 bearing against the rear face of the said block and secured to the spindle by a nut 40. The other end of the spindle is provided with a disk 50 to which is secured the upper contact preferably in the form of a ring 41, the edge of which is located directly above the contact shoe 24 of the work support or mandrel 23'. When the work, located between the contact-shoe 24 and the contact ring 41 is progressively fed through the machine by means of the travel of the carriage 9, the heating current passes from the contact ring 41 to the contact-shoe 24 or workholder 23 through the work, the contactring 41 being rotated in the block 34 by the travel of the work-holder. The upper contact 41 is preferably made in the form of a ring fitted to the spindle 38 and having its linner periphery bearing on a hub formed on or secured to the disk 50 as shown so that when it is desired to replace it, owing to wear or damage, less new material will have to be employed than if the contact was made as a solid plate,l and also by this construction the contact proper has a more solid bearing and the jar does not tend to loosen or break the fastening screws. The ordinary wear of the edge of the roller contact 41 is taken up by adjusting the position of the block 34 by means of the nuts 36 as previously described.

The slide 33 carrying the roller lcontact 41 moves vertically, or transversely to the line of travel of the work-holder 23, to cause the contact 41 to engage, or be disengaged from, the work and is supported in the following manner. The upper part of the slide 33 is provided with a rearwardly projecting boss 42 to which is secured a stud 43. A rockshaft 45 journaled in the bracket 30 has a lever 44 keyed to one end thereof. The free end of the lever engages the lower end of the stud 43 and carries and supportsthe.

slide 33 and its attendant parts. A lever 46 keyed to the other end of the rock-shaft 45 is connected by a pivcted link 47 with mechanism controlled by the travel of the carriage 9 and adapted to rock the shaft 45 to cause the lever 44 to raise the slide 33 or to permit it to drop, which controlling mechanisrn will be hereinafter described.

When the end of the lever 44 is depressed to permit the slide 33 to drop to cause the roller contact 41 to engage the work, the slide 33 drops due partly to the weight of the parts carried by it and also by the action of a spring 48 compressed between the slide 33 and the bracket 30,' the force exerted by the spring being adjusted by a regulating screw 49. By means of this spring pressure, as soon 'as the slide 33 is released bv the depressing of the lever 44, the slide will immediately be forced down to cause the contact 41 to engage the work, the suddenness of the descent being regulated by the s crew 49. The spring 48 also ,supplies the welding pressure to the contact roller 41 which pressure might be varied according to the kind of Work, or as desired, by the regulating screw 49. When the end of the lever 44 is raised, the slide 33 and contact 41 are drawn up from the work against the action of the spring 48 which is again compressed and stores energy to force the contact down when again released.

As the current is conducted from the block 34 to the roller contact 41 by means of the contact of the spindle 38 with the block 34 and as the amount of current which reaches the roller contact will therefore depend upon the accuracy of the bearing between the spindle and block which bearing is apt to become worn, it is preferable to provide a. direct connection between the block 34 or secondary 7 and the roller-cone tact to prevent sparking and thereby destroying the bearing and also to insure that the full current will be transmitted. This connection operates as a shunt around the roller bearing and consists of a brush 51 constructed preferably of' copper ribbons bearing on the periphery of the disk 50, see Fig. 18, and mounted on a bracket 52 secured to the block 34 in electrical connection therewith.

53 indicates a blade spring secured to a support 54 pivotally mounted on the bracket 52 and carries a mass of cleaning material 55 such as line emery, or other lsuitable material which is adapted to rub on the contact edge of the ring 41 to wipe off any dirt and to keep the contact edge clean and bright to insure a perfect contact with the Work. The amount of pressure between the cleaner 55 and the edge of the contact 41 is regulated by a screw 56 secured to the bracket 52 and operating on the support 54.

Tlie'mechanism for adjusting the overlapping edges of the work, if a lap Weld desired, and the mechanism for clamping the work on the support or mandrel 23 will now be described and for the purpose of more clearly lshowing the construction we Will refer more particularly to Figs. 19, 21, 22, 23 and 24.

57 and 53 indicate brackets mounted on the carriage 9, suitably insulated therefrom and adapted to travel with thc carriage. The brackets are located one on either side of the Work-holder or lnandrel 23 and ou each is mounted the locating stops and clamps for the work. As each bracket is similar to the other and both carry similar devices operating in the same way. but one of them with its attendant mechanism will be described, it being understood that the description v'ill apply to both.

59 indicates a rock-shaft journaled on eccentric bracket 58. The forward pivot 6l projects somewhat beyond the support 60 and to it an operating handle or lever 62 is secured for rocking the shaft 59. A rack 63, loosely mounted on the rock-shaft 5,9 between the supports 60, is provided with a number of laterally projecting locating stops or fingers 64 which are movable transversely onto the mandrel or work-holder 23 to adjust the edge of the work by means of the handle 62. lThe stops or fingers 64 are preferably spaced apart and of sufficient number to provide an abutment againstwhich the entire edge of the'work` strikes, the stopsv being withdrawn by a reverse movement of the handle or lever 62.

` Any suitable means for limiting and varying the amount of transverse movement of the stops 64 might be employed but we prefer to employ for this purpose, an -adjustable stop 65 secured to the support 60, which when the lever 62 is broughtV over to move the stops 64 into adjusted position will strike a laterally projecting lug 66 secured to the lever 62 andprevent further movement of lthe lever. In the reverse movement, the stops or fingers 64 are preferably brought to rest by the lever strlkinn' a nin 67 projecting laterally from the support 60. i

The mechanism for clamping Athe edge of the work after it has been adjusted by means of the locating fingers 64 consists preferably of a clamping lever made up of a v number of clamping devices or fingers 68 i fulcrumed on a shaft 69 secured to the supports 60. Thev clamping devices are located parallel with the adjusted edge of the work or the line of the seam, and lpreferably enter the spaces between the locating fingers G4, a sufficient number of them being provided to engage the work along the en tire length of theseani or edge. The clamping fingers 68 are brought into clalnpmg position to grip and hold the work between Vthem and the work-support 23 by means ot" a clamping screw 70 bearing on the bracket 58 and operating on an arm 71 of the clamping lever. By turning the screw 70 1n one direction, the arm 71 will be forced up and the clamping fingers 68 pressed on the work, While to release the work, the screw 70 is turned in the reverse direction.

72 indicates a spring coiled around the rock-shaft 59, one end of which bears upon the locating fingers 64 to keep them pressed against the mandrel 23 or on the work, while the other end bears on the arm 71 and works against'the action of the clamping screw to force the clamping fingers or lever away from the work when the clamping screw 70 is released, the spring acting to keep the end of the screw 70 pressed against its seat on the bracket`58.

lVhen the two edges of the Work are clamped by the opposite sets of clamping fingers 68 and the vwork is progressively fed into engagement with the roller contact 4l by the travel of the carriage 9, the contact 41 engages and travels along the work in the space between the clamping fingers 68, the locating stops 64 having been previously Withdrawn. J

XVe will now describe the driving mechanism for causing the work to be progressively fed into engagement with the roller contact, together with the automatic stopping of the feeding operation and the devices for returning the carriage to its original position, after which the mechanism for raising the roller contact free from the work will be described and then the devices for automatically controlling the fiow of heating current through the work.

Referring more particularly to Figs. 3, 4, 5, 17, 25, 26, 27, 28, 29 and 30, the driving shaft indicated at 73 is arranged transversely to the line of travel of the carriage `shaft 74 to which is secured an ordinary belt-pulley 75. A pinion 76 fast upon the counter-shaft 74 meshes with a gear wheel 7 mounted on a stud 78 secured to the frame of the machine. A gear wheel 79 keyed to the end of the driving shaft 73 meshes with. a pinion 80 secured to the gear wheel 77, by which train of gears the gear wheel 79 continuously revolves the driving shaft 73 as long as the belt or other driving power is coupled to the counter-shaft 74.

81 indicates a toothed rack secured to the underneath side of the carriage 9 and located longitudinally therewith in the opening l1 in the table 1. The teeth of said rack /depend from it and are continuously 1n rmesh with the teeth of a gear-wheel 82 loosely mounted on the driving shaft 73 but vsuitably prevented .from longitudinal displacement thereon.

Any suitable form yof clutch for coupling the gear-wheel 82 to the driving shaft 73 might be used but we prefer to employ a clutch in which the two members engage each other by the meshing of laterally project'mg teeth secured to each member of the clutch as by this construction great strength 1s obtained andthere is no liability of the clutch slipping. Preferably the clutch employed, and hereinafter termed the powerclutch, consists of a fixed member 83 which rotates with the shaft 73 but is free to move longitudinally on a feather thereon to cause it to engage the other or loose member of the clutch. A toothed disk 84-secured to the face of the member 83 is adapted to mesh gear wheel 82, forming the loose member `of the clutch, when the fixed member 83 is moved longitudinally thereto, which engagement causes the gear wheel 82 to be coupled to the driving shaft. A forked lever 86 provided with pins in the periphery of the fixed clutch member 83 is keyed to a rock-shaft 88 mounted in bearings in a bracket 89 secured to a convenient part of the frame, so that by rocking the shaft 88, the members of the clutch are either coupled or uncoupled according to the direction of rotation or rocking of the shaft 88, the clutch member 83 being limited in its uncoupling movement by striking the frame 3. A tension spring 90 secured to the frame of the machine and an arm 91 secured to the lever 86 normally tends to uncouple the clutch by drawing the member 83 back- -ward.r

When it is desired to connect the carriage 9 to the driving power, the shaft 88 is rocked to `couple the members of the clutchby the following mechanism: An arm 92 keyed to the rock-shaft 88 is pivotally connected to an operating rod 93 by a link 94, said operating rod being supported in bearings formed in a bracket 95. If the rod 93 is pulled down the shaft 88 will be rocked and cause thel lever 86 to force the two members of the clutch together against the action of thespring 90. A bell-crank lever 96 pivotally mounted on a bracket 97 carries on one arm a pivoted latch 98 which engages a collar 99 secured to the rod 93, the said latch being normally held against said collar by a spring 100. The other arm of the bell- 'crank lever is connected by a pivoted link 101 to a foot treadle 102 pivotally mounted on a stud 103 secured to thes frame. Upon pressing the foot treadle the rod 93 will be forced downward by the latch 984 and the collar 99 and the carriage 9 will be coupled to the driving shaft 73 through the clutch 83 as previously described. It is necessary 'to keep the treadle 102 pressed downward to prevent the clutch from` disengaging, as if the treadle was released the operating rod -93 would be drawn upward by the rocking of the shaft 88 in the reverse direction due to the action of the sprin 90 and the clutch would be uncoupled. owever, means for automatically uncoupling the power clutch when the treadle is retained in depressed position is rovided and will presently be described. Vhen the treadle 102 is released it is drawn upward by the action of a spring 104, its upward movement being limited by a stop 105.

106 indicates a block or nut secured to the carriage 9 and adapted to travel with it, but capable of being adjusted longitudinally for different lengths of weld it might bev desired to obtain. By adjusting the longi- 87 engaging a groove tudinal position of this nut, the point at which the power-clutch is uncoupled can be varied, or in other words, the length of travel of the carriage determined. The nut 106 works in longitudinally disposed guides 108 and 113 secured to the carriage 9. An adjustment screw 109 having a threaded connection with the nut 106 is secured to the carriage 9, one end being supported'in a lug 110 and the other end preferably journaled in a block 111 secured to the carriage 9. By turning the screw 109 by means of the head 112 the longitudinal position of the nut 106 can be varied.

114 indicates a lever for releasing the rod l93 from the latch 98 and is fixed to a shaft 115 journaled in a bearing secured to the frame 3. The lever 114 is located so that the end thereof will be in the path of, and struck by, a trip 116 secured to the nut 106 when the carriage trav'els sufficiently far for the trip to reach the lever 114. An arm 117 fixed to the shaft 115 is pivotally connected by a rod 119 and an arm 120 to a rock shaft 118 mounted in the bracket 97. The shaft 118 carries a cam 121 which, when the shaft is rocked engages the end of the latch 98 and forces the latch away from the collar -99 which releases the rock-shaft 88 and permits the spring 90 to 'uncouple the powerclutch, the parts taking the position shown in Fig. 30. When the carriage has traveled sufficiently far for the trip 116 to strike the lever 114, the lever 114 will be turned and actu-ate the rock shaft 118 to cause the cam 121 to release the rod 93 as above pointed out. As soon as the carriage starts its travel in the reverse direction toreturn to its initial position, the lever 114 is freed from the trip 116 and the rock-shaft 118 and its attendant parts return to their normal position by the action of -a spring 122, the lever 114 normally remaining 'in position against the stop 123. By varying the distance between the trip 116 and the lever 114 by means ofv the adjustment nut 106` the amount of travel of the carriage 9 can be increased or decreased as desired, as the forward movement of the carriage will Vcontinue until the trip 116 strikes'the releasing lever 114. Upon releasing the treadle 102', the catch 98 will return to the position shown in Fig. 25.

To insure the immediate uncoupling of the power-clutch when the rod 93 is released, it is desirable to supply additional means for positivelydriving the members of the p is possible to uncouple the clutch by the action of the ,spring alone, although quick actin can be more depended upon by employing the above described means.

Having described the mechanism for automatically stopping the forward travel of the carriage, we will now describe the means for returning the carriage to its initial position and refer more particularly to Figs. 6, 7, 17 and 28.

A sprocket-Wheel 127 secured to the gear# wheel 82, which meshes with the driving rack 81, and located between it and the frame 2, is connected by a sprocket chain 128 toa sprocket-wheel 129 loosely mounted on a shaft 130 disposed parallel to the driving shaft 73. A gear wheel 131 fixed to the shaft 130 is actuated by a pinion 132 in mesh therewith, said pinion bein mounted on a stud secured to the table 1 an provided with a crank-handle 133.v When it is de; sired to rotate the shaft 130, the rotation is effected by turning the handle 133' which rotates the shaft 130 through pinion 132 and gearf 131. To couple the loosely mounted sprocket 129 to the shaft 130, la toothed disk 134 secured to the sprocket 129 is engaged by the teeth of a similar disk 135 secured to a fixed clutch member 136 when the said fixed clutch member is moved longitudinally toward it.

137 indicates a foot treadle connected by avpivoted rod 138 to one arm of a pivotally mounted forked lever 139. |The forked lever is provided with suitable pins which engage a groove in the periphery of the fixed clutch member and by pressing the foot treadle 137 the clutch member 136 is moved into engagement with `the member 134 and the sprocket 129 is coupled to the shaft 130. Upon releasing the foot treadle the clutch members are uncoupled `by the action of a spring 140 acting on the clutch operating lever 139, the movement of `the clutch member 136 being limited by a suitable stop such as a collar 141 secured to the shaft 130. When the sprocket wheel 129 is coupled to the shaft 130 by means of the clutch members 134, 135 and the shaft rotated by the crank handle 133 inthe proper direction, the gear wheel 82 will be rotated by the chain -128v and sprocket 127 to return the carriage to its normal position through the connection of the gear wheely 82 with the rack 81 secured to the carriagef9.

The return of the carriage 9 is effected as above described while the driving shaft 73 described.

is rotating, as the gear 82 is loose on the shaft 73 when it is desired to return the carriage. When the gear-wheel 82 is coupled to` the vshaft 73 to propel the carriage forward, the sprocket wheels 127 vand 129 will rotate with it, but this rotation will not affect the shaft 130 as the sprocket 129 is atthat time loose upon the shaft.

We will now describe the mechanism for lowering and raising the roller contact 41 into and out of position to engage the work, the said lowering and raising being automatically controlled by the travel of the carriage* 9 or work-holder 23. As more clearly illustrating the mechanism we will refer particularly to the detail views, Figs. 3, 4, 5 and 1o.

142 indicates a lever by whose movements the roller contact 41L is raised or is permitted to ,drop through the action of the spring v48 and weightof the parts as previously y The lever A142 is mounted on a stud 143 secured to a suitable part of the frame ofthe rmachine and is provided with a depending arm 144 pivotally connected to an arm 145 by a link 146. The arm 145 is mounted on a rock-shaft 147 which also car'- ries an arm 148 to which the link 47 is pivoted. The link 47 being connected with the contact raising lever 44 as previously described, it will be noted that any movement of the lever 142 about its pivot 143 will cause the lever 44 to either raise the slide 33 or permit it to drop. One arm of the lever 142 is provided with a cam roll or follower 149 and the other arm is provided with a shoulder 150 which is adapted to be engaged by a pivoted latch 151. If the cam follower 149 rises, the roller contact 41 is permitted to drop to engage the work. Normally when the machine is not doing any Ywork, the cam roll 149 is preventedl'from rising by asolid obstruction againstwhich it rests. This obstruction is preferably part of or secured to the carriage 9 so that when the carriage starts to'travel the obstruction will be removed (by traveling with the carriage) and permit the cam-roll on the lever 142` to rise and the contact-roll 41 to drop.

'The obstruction preferably consists of a plate 152 rigidly secured to the carriage 9 and provided with a face cam 153. The cam-roll 149 normally rests on the rise of the cam 153 but when the carriage starts forward` the cam-roll is released and permits the arm of the lever'142 carrying the cam-roll to rise due to the withdrawing of the obstruction and the descent of the slide 33 and roller contact 41. A plate 154, provided with a face cam 155, secured to the adjustment nut 106 engages the cam-roll 149 upon the further movement of the carriage, depresses the lever 142-and thus raises the roller contact 41. When the lever 142 is engaged by the cam 155 and depressed, the

latch 151 engages the shoulder 150 by the action of the spring consequently the roller contact from descending, when the roll 149 has been freed from the cam 155 bythe return movement of the carriage.

The cam 155 is preferably higher thanv the cam 153 and of such height that when it strikes the cam-roll 149 the latch 151 will be forced under the shoulder 150 by the action of the spring 156. When, vby the return movement of the carriage, the lever 142 is freed by the trip 157, the cam-roll 149 will rise until it is stopped by the cam 153 which however is a higher point than that at which it rested' when'engaged by the cam 155. This increased height of the cam-roll 149 permits the shoulder to drop suiiiciently so that when the carriage again starts on its forward travel, the latch 151 will not be permitted to engage the shoulder 150 and thus prevent the descent of the roller contact.

A trip 157 secured to the carriage 9 engages and trips the latch 151 on the completion of the return movement of the carriage, the contact 41 beingI then prevented from descending by the engagement of the roll 149 with the cam 153. By releasing the lever 142 from the influence of the latch, it again becomes free to rise when the cam 153 has been removed by the .next forward movement of the carriage. 4

By mounting the contact raising cam 155 on vthe adjustment nut,106, the length of engagement of the roller contact with the work can be varied to accommodate the machine for different lengths of weld.

It will be obvious that the heating current should begin to flow through the work as soon as the roller contact engages the work and should. be -broken ofi' immediately before or at the instant the contact rises free of the work. As it would be practically impossible to close the circuit by hand at eX- actly theright instant when it is desired to start the weld and also to break the circuit at the correct moment, the making and breaking of the circuit controlling the flow of heating current to the work is automatically brought about by, and dependent upon, the travel of the carriage.

Referring to Figs. 3, 4, 5, 13, 14, 15 and 16 as giving the clearest illustrations of the circuit controlling devices, the circuit controller proper might be any suitable typ of switch preferably located in the primary circuit so that, upon opening the switch the primary circuit is broken and thus the flow through the secondary is stopped. f

The circuit-breaker or controller is sup.- ported on a table 158 secured to the base of the machine. 159, indicates the lever for making and breaking the circuit and is piv- 156 and prevents the y preferably formed of a .a base 161 secured to the table 158. A contact 162 is secured to, but suitably insulated from,.the end of the lever 159 and is introduced into the electric circuit by means of a wire 163 secured thereto. The contact 162 is adapted to engage a iixed contact 164 secured to a binding post 165 by a lead 166 'number of thin strips vof vsheet copper so that the contact 164 will be capable of yielding slightly to the pressure of the contact 162 when brought intoV engagement with it. A spring 167 acts on the contact .1 64 to keep it pressed against the contact 162, a stop 168 limiting the action of the spring 167 when the contact 162 has been withdrawn. The binding post 165 is secured to and insulated from the base 161 and forms the terminal of the other end of the circuit wire 169.

The closing lever 159 is provided )with an arm 170 pivotally connected with an arm of a bell-crank lever 171 by a link 172, said bell-crank lever being pivotall mounted on the bracket 160. A spring 1 3 referably acting on the bell-crank 171 ten s to close the contact of the lever 159 on the contact 164 and start the iow of current but is re-Y strained from so acting at all ti'mes except when it is desired to pass the heating current through the work aby the following mechanism: 174 indicates a bell-crank lever pivotally mounted as at 175 to a frame of the machine or a bracket secured thereto,

and is connected to the lever 171 by a pivoted link 176. The short arm 177 of the lever 174 is provided with a ledge or projection 178 (see Fig. 14) which, when the carriage is at rest and in its initial position, is engaged by a stop 17 9 to hold the circuitbreaker in open position against the action of the spring 173. The stop 179 is secured to the carriage 9 so that as the carriage travels forward the arm 177 of the bellcrank 174 is freed from the stop 179 and the circuit controller is closed by the spring 173. The bell-crank 174 is provided with a vertical projection 180 secured to the arm 177 which, upon the carriage traveling lforward `is hit by a trip 181 mounted on the adjustment nut 106 which action by the trip 181 breaks the circuit by resettlng the crank lever 174. .When the arm 177 is depressed by the trip 181, a pivoted latch 182 engages the ledge 178 by the action of a spring 183.

The circuit controller is now held in open position by means of the latch 182 durlng the return movement of the carriage.

When the carria returns to its initial ositon, the side '0 the stop 179 strikes the atch 182 and acts asa trip to free'the crank lever 174 from the latch 182, the crank lever being now held by the stop 179 andthe circuit broken until the carriage begins its forward movement again. 

